What's this then?

[svenedin]

The chimney usually contains a sort of wire wool (usually a rusty mess unless cleaned out; mine was). It is an oil trap and maybe a flame arrester. The chimney is supposed to be connected to either a PCV valve on the inlet manifold or to a “breather” type carburettor. In other words the chimney is an exit for crankcase gasses and then a breather oil cap is an inlet. With that system the rocker cover does not have any pipe attached.

Your system would appear to be working in reverse to what was intended. The rocker pipe is attached to vacuum via the air cleaner and the chimney pipe open to atmosphere and presumably acting as an inlet. Perhaps your system still works that way. Does the engine leak oil?

Stephen

[philthehill]

As the inlet manifold does not have the hole for the PCV valve the canister breather would normally be vented to/through the carb.
A photo of the rear of the carb so as to determine if the carb is the vented type would be appreciated.
It may be that the canister breather has been fitted as an after factory addition.
The air cleaner type suggests that the rocker cover is the correct type. Whether the oil filler cap is the right one is to be determined.

[svenedin]

As the inlet manifold does not have the hole for the PCV valve the canister breather would normally be vented to/through the carb.
A photo of the rear of the carb so as to determine if the carb is the vented type would be appreciated.
It may be that the canister breather has been fitted as an after factory addition.
The air cleaner type suggests that the rocker cover is the correct type. Whether the oil filler cap is the right one is to be determined.

My car (1969) does have an inlet manifold with the hole for a PCV valve AND an air filter with the stub to attach a breather pipe. I don't think they changed the design of the air filter when they switched to the chimney breather arrangement.

[Bandage]

Had a look on the other side of the carb (see attached), and can't see an obvious inlet valve, so no, not the vented type.

Looking through the paperwork that she came with, it had a new carb three years ago, and the MOT mileage shows that the engine was replaced in 1995. (or had a new speedo?) All things considered, I'd be surprised if this is how it came out of the factory!

As for oil leaks, not really. A few drips each day, but nothing major.

[philthehill]

You are correct in that the carb fitted is not the carb used with the breather canister.
Either the manifold has been replaced (excluding the PCV valve) or the cam follower cover with breather has been replaced.
Either way I would not be concerned so use and enjoy.
Phil

[svenedin]

You are correct in that the carb fitted is not the carb used with the breather canister.
Either the manifold has been replaced (excluding the PCV valve) or the cam follower cover with breather has been replaced.
Either way I would not be concerned so use and enjoy.
Phil

Exactly. It seems to work even if non-standard. It’s not leaking oil so crankcase breathing is working. One think I would check is inside the oil filler cap. If there is a cottage cheese like substance there it suggests the crankcase breathing arrangement is not as good as it should be. I had that symptom until I sorted out the breathing. If nothing there just enjoy the car.